Current through all regulations passed and filed through September 16, 2024
[Comment: For dates of non-regulatory government publications,
publications of recognized organizations and associations, federal rules, and
federal statutory provisions referenced in this rule, see paragraph (C) of rule
3745-104-01 of the
Administrative Code titled "Referenced materials."]
(A) The owner or operator shall analyze and
report in the RMP:
(1) For program one
processes, one worst-case release scenario for each program one process.
(2) For program two and three processes:
(a) One worst-case release scenario that is
estimated to create the greatest distance in any direction to an endpoint
provided in the appendix to rule
3745-104-09
of the Administrative Code resulting from an accidental release of regulated
toxic substances from covered processes under worst-case conditions defined in
rule
3745-104-09
of the Administrative Code.
(b) One worst-case release scenario that is
estimated to create the greatest distance in any direction to an endpoint
defined in paragraph (A) of rule
3745-104-09
of the Administrative Code resulting from an accidental release of regulated
flammable substances from covered processes under worst-case conditions defined
in rule
3745-104-09
of the Administrative Code.
(c)
Additional worst-case release scenarios shall be reported if a worst-case
release from another covered process(es) at the stationary source potentially
affects public receptors different from those potentially affected by the
worst-case release scenario developed under paragraph (A)(2)(a) or (A)(2)(b) of
this rule.
(B) Determination of worst-case release
quantity. The worst-case release quantity shall be the greater of the
following:
(1) For substances in a vessel, the
greatest amount held at any time in a single vessel, taking into account
administrative controls that limit the maximum quantity.
(2) For substances in pipes, the greatest
amount at any time in a pipe, taking into account administrative controls that
limit the maximum quantity.
(C) Worst-case release scenario: toxic gases.
(1) For regulated toxic substances that are
normally gases at ambient temperature and handled as either a gas or handled as
a liquid under pressure, the owner or operator shall assume that the quantity
in the vessel or pipe, as determined under paragraph (B) of this rule, is
released as a gas over ten minutes. The release rate shall be assumed to be the
total quantity divided by ten unless passive mitigation systems are in place at
the covered process.
(2) For gases
handled as refrigerated liquids at ambient pressure:
(a) If the released substance is not
contained by passive mitigation systems or if the release is contained and the
contained pool would have a depth of one centimeter or less, the owner or
operator shall assume that the substance is released as a gas in ten
minutes.
(b) If
the released substance is contained by passive mitigation systems in a pool
with a depth greater than one centimeter, the owner or operator may assume that
the quantity in the vessel or pipe, as determined under paragraph (B) of this
rule, is spilled instantaneously to form a liquid pool. The release rate shall
be calculated at the boiling point of the substance and at the conditions
specified in paragraph (D) of this rule.
(D) Worst-case release scenario: toxic
liquids.
(1) For regulated toxic substances
that are normally liquids at ambient temperature, the owner or operator shall
assume that the quantity in the vessel or pipe, as determined under paragraph
(B) of this rule, is spilled instantaneously to form a liquid pool.
(a) The surface area of the pool shall be
determined by assuming that the liquid spreads to one centimeter deep unless
passive mitigation systems are in place at the covered process that serve to
contain the spill and limit the surface area. Where passive mitigation is in
place, the surface area of the contained liquid shall be used to calculate the
volatilization rate.
(b) If the
release would occur onto a surface that is not paved or smooth, the owner or
operator may take into account the actual surface characteristics.
(2) The volatilization rate shall
account for the highest daily maximum temperature occurring in the past three
years, the temperature of the substance in the vessel, and the concentration of
the substance if the liquid spilled is a mixture or solution.
(3) The rate of release to air shall be
determined from the volatilization rate of the liquid pool. The owner or
operator may use the methodology in the "RMP Offsite Consequence Analysis
Guidance" or any other publicly available techniques that account for the
modeling conditions and are recognized by industry as applicable as part of
current practices. Proprietary models that account for the modeling conditions
may be used provided the owner or operator allows the director or the
director's representative access to the model and describes model features and
differences from publicly available models to local emergency planners upon
request.
(E) Worst-case
release scenario: flammable gases. The owner or operator shall assume that the
quantity of the substance, as determined under paragraph (B) of this rule and
the provisions below, vaporizes resulting in a vapor cloud explosion. A yield
factor of ten per cent of the available energy released in the explosion shall
be used to determine the distance to the explosion endpoint if the model used
is based on TNT equivalent methods.
(1) For
regulated flammable substances that are normally gases at ambient temperature
and handled as a gas or as a liquid under pressure, the owner or operator shall
assume that the quantity in the vessel or pipe, as determined under paragraph
(B) of this rule, is released as a gas over ten minuteswith the total
quantity assumed to be involved in
the vapor cloud explosion.
(2) For
flammable gases handled as refrigerated liquids at ambient pressure:
(a) If the released substance is not
contained by passive mitigation systems or if the contained pool would have a
depth of one centimeter or less, the owner or operator shall assume that the
total quantity of the substance is released as a gas in ten minutes, and the
total quantity will be involved in the vapor cloud explosion.
(b) If the released substance is contained by
passive mitigation systems in a pool with a depth greater than one centimeter,
the owner or operator may assume that the quantity in the vessel or pipe, as
determined under paragraph (B) of this rule, is spilled instantaneously to form
a liquid pool. The volatilization rate (release rate) shall be calculated at
the boiling point of the substance and at the conditions specified in paragraph
(D) of this ruleand assuming that the quantity
which becomes vapor in the first ten minutes is involved in the vapor cloud
explosion.
(F) Worst-case release scenario: flammable
liquids. The owner or operator shall assume that the quantity of the substance,
as determined under paragraph (B) of this rule and the provisions of this
paragraph, vaporizes resulting in a vapor cloud explosion. A yield factor of
ten per cent of the available energy released in the explosion shall be used to
determine the distance to the explosion endpoint if the model used is based on
TNT equivalent methods.
(1) For regulated
flammable substances that are normally liquids at ambient temperature, the
owner or operator shall assume that the entire quantity in the vessel or pipe,
as determined under paragraph (B) of this rule, is spilled instantaneously to
form a liquid pool. For liquids at temperatures below their atmospheric boiling
point, the volatilization rate shall be calculated at the conditions specified
in paragraph (D) of this rule.
(2)
The owner or operator shall assume that the quantity which becomes vapor in the
first ten minutes is involved in the vapor cloud explosion.
(G) Parameters to be applied for
all covered processes. The owner or operator shall use the parameters defined
in rule
3745-104-09
of the Administrative Code to determine distance to the endpoints. The owner or
operator may use the methodology provided in the "RMP Offsite Consequence
Analysis Guidance" or any commercially or publicly available air dispersion
modeling techniques, provided the techniques account for the modeling
conditions and are recognized by industry as applicable as part of current
practices. Proprietary models that account for the modeling conditions may be
used provided the owner or operator allows the director or the director's
representative access to the model and describes model features and differences
from publicly available models to local emergency planners upon
request.
(H) Consideration of
passive mitigation. Passive mitigation systems may be considered for the
analysis of worst case provided that the mitigation system can withstand the
release event triggering the scenario and would still function as
intended.
(I) Factors in selecting
a worst-case scenario. The owner or operator shall select as the worst case for
flammable regulated substances or the worst case for regulated toxic
substances, a scenario that would result in a greater distance to an endpoint,
as defined in paragraph (A) of rule
3745-104-09
of the Administrative Code, beyond the stationary source boundary
and
be based on the following:
(1) Determination of worst-case release
quantity as defined in paragraphs (B)(1) and (B)(2) of this rule.
(2) Smaller quantities handled at higher
process temperature or pressure.
(3)
Proximity to the boundary of the stationary source.
